Risks and Benefits of Alcohol Use Over the Life Span

Especially at low and moderate drinking levels, alcohol consumption can be associated with benefits (e.g., protection against coronary heart disease) as well as risks (e.g., increased risk of accidents). These benefits and risks may change across a person’s life span. To determine the likely net outcome of alcohol consumption, one must weigh the probable risks and benefits for each drinker. These assessments are based on the individual drinker’s consumption levels, his or her personal characteristics (e.g., age or preexisting risk factors for coronary heart disease), and subjective values as well as on social considerations. The validity of such assessments also depends on the accuracy with which alcohol consumption and alcohol-related consequences can be measured.

T he consumption of alcoholic met the criteria of the American Psy prom car crashes shares the media beverages has been a part of chiatric Association's Diagnostic and spotlight with reports on the cardio many cultures since at least the Statistical Manual of Mental Disorders, protective effects of lowlevel alcohol beginning of recorded history. Ancient Fourth Edition (DSM-IV) for alcohol consumption. Traffic statistics and news texts from Persia, Egypt, Babylon, abuse and dependence (Grant et al. reports, however, do not answer the Greece, and China, as well as Biblical 1994). The alcoholrelated costs to the question, What are the health risks and writers, have documented that people Nation have been estimated to include benefits of alcohol consumption for have been aware of alcohol's beneficial 100,000 deaths and nearly $100 billion a given person? This article defines and harmful effects for nearly as long as each year (Rice 1993). alcoholrelated risk, reviews several people have been drinking (Rubin and Although moderate alcohol use has beneficial and detrimental conse Thomas 1992). Alcohol consumption been sanctioned in the United States quences of alcohol consumption, and also is clearly a part of contemporary for a long time, its objective benefits describes approaches to determining American life. As a result, although have begun to be quantified only re a person's net risk or benefit from al most people drink moderately and with cently. For example, a substantial body cohol consumption. out ill effect, alcohol abuse and alcohol of literature now exists describing the dependence are major health problems protective effects of lowlevel alcohol DEFINING ALCOHOL in the United States. In 1992 almost consumption against coronary heart CONSUMPTION AND ALCOHOL 14 million Americans age 18 and older disease, as evidenced primarily by the RELATED RISK reduced risk of death from acute heart MARY C. DUFOUR, M.D., M.P.H., is attacks (Klatsky et al. 1992). Any discussion of the risks and benefits deputy director of the National Insti The public also has become aware of alcohol consumption must address tute on Alcohol Abuse and Alcoholism, of alcohol's general risks and benefits: the issue of defining relevant terms. For Bethesda, Maryland.
News of grisly, alcoholrelated, post example, few people would disagree that "excessive" drinking is harmful. Attempts to define "excessive" pre cisely, however, are likely to generate considerable discussion. Similarly, the terms "abstainer," "light," "moderate," "heavy," and "heavier" are commonly used to describe types of drinkers, al though no standard definitions exist for these drinking levels. Many stud ies refer to respondents in the drink ing category with the lowest mortality as "moderate drinkers" (Ferrence and Bondy 1994). Consequently, the def inition of moderate drinking varies substantially across studies, ranging from less than one drink per day to three or more drinks per day (Fer rence and Bondy 1994). The defini tions of what constitutes a "drink" are equally variable. This definitional vagueness can lead to considerable confusion in interpret ing epidemiological studies investigat ing the relationship between alcohol consumption and various risks and benefits. For example, people who intend to drink for cardioprotection need to know at what level of alcohol consumption such benefits accrue (i.e., how many and what size drinks constitute "moderate" drinking) and which additional risks are associated with that drinking level.
To be useful concepts, the risks and benefits associated with alcohol con sumption also must be specified. For example, risks or benefits may be short term (i.e., acute), affecting the drinker within hours or days, or long term (i.e., chronic), exerting their ef fects over many years. Acute risks often arise from consumption of a large volume of alcohol in a short period of time. These risks include car crashes, violence, and alcohol poisoning as well as alcoholmedication interactions. Longterm risks include chronic diseases, such as alcohol de pendence, alcoholic cirrhosis, and alcoholic heart muscle disease (i.e., cardiomyopathy). Among the acute benefits of alcohol consumption, im proved mood (i.e., happiness and euphoria) probably is the most com mon (Dufour 1994). Alcohol's cardio protective effects appear to be both acute (e.g., decreased platelet adhe siveness in the blood, which reduces the danger of developing blood clots that may lead to heart attacks and strokes) and chronic (e.g., increased levels of high density lipoproteins, or "good" cholesterol) (Jackson et al. 1992). These examples illustrate the importance of specifying exactly which risks and benefits are associated with each alcoholconsumption level.

The Concept of Net Outcome
The dichotomous view that alcohol is either only beneficial or only harmful is too simplistic; a more reasonable approach is the assessment of net out come. This approach totals the positive and negative consequences of a per son's alcohol consumption to arrive at a net benefit or net risk for that person at his or her specific consumption level.

The dichotomous view that alcohol is either only beneficial
or only harmful is too simplistic.
For example, the determination of a net benefit implies that for a particu lar drinker, the benefits of drinking outweigh the risks. A disadvantage of the concept of net outcome is that it assumes that one can separate the effects of alcohol from those of other confounding fac tors. Alcohol's effects, however, can not be considered in isolation. Some research suggests that moderate drinkers differ from abstainers and other drinkers not only in alcohol consumption but also in other health related characteristics. For example, according to the Disease Prevention and Health Promotion Supplement to the 1985 U.S. National Health Inter view Survey, moderate drinkers were more likely than either abstainers or other drinkers to sleep 7 to 8 hours each night, be at their ideal body weight, and exercise regularly (Dufour 1994). Each of these factors can con tribute to good health, and their effects are difficult to disentangle from the effects of alcohol consumption per se.
The concept of net outcome re quires a multidimensional frame of reference. For example, the relation ships among the multiple factors that contribute to alcohol's net effects (e.g., the drinker's physical and psy chological condition or social envi ronment) may change over time. In addition, the assessment of correla tions between current drinking levels and potential future consequences may be complicated by the fact that alcohol consumption is a dynamic process and can fluctuate over the short term (i.e., weeks) as well as over the long term (i.e., years). The implications of this variability can be illustrated best by using another medical parameter as an example: Blood pressure is extremely variable over the short term (i.e., the course of the day); nevertheless, a single blood pressure measurement fairly accurately reflects overall blood pressure at that point in time. Moreover, current hypertension could predict a worse outcome (e.g., an increased risk of a heart attack) in the future com pared with normal blood pressure. Longterm changes in blood pressure (e.g., through treatment for hyperten sion), however, also would affect future outcome, making the risk and, therefore, the net outcome intermedi ate between normal blood pressure and untreated hypertension. By the same token, changes in alcohol con sumption over the life span can influ ence certain associated risks and benefits and thus alter net outcome.

ASSESSING RISKS AND BENEFITS OF ALCOHOL CONSUMPTION
Because death is the easiest health in dicator to assess, mortality-either from all causes combined or from specific causes-frequently is used to evaluate the health risks associated with certain drinking levels (see figure). (For infor mation on assessing risk based on per capita alcohol consumption, see side bar, pp. 148-149.) The findings of these analyses, however, are not always un equivocal. For example, Jackson and Beaglehole (1995) found that the risks associated with heavier drinking 1 clearly outweighed the benefits associated with this level of alcohol consumption. In contrast, the risktobenefit balance for lower levels of alcohol consumption was not as obvious. On the one hand, lighttomoderate drinking appeared to reduce the relative risk of dying from coronary heart disease by as much as 50 percent, and light drinking also low ered the risk of death from ischemic stroke. 2 On the other hand, lightto moderate drinking increased mortality from cirrhosis, injury (e.g., suicides and car crashes), hemorrhagic stroke, breast cancer, and, possibly, bowel cancer.
The net outcome of allcause mor tality associated with a certain alcohol consumption level therefore also depends on the drinker's absolute risk of dying from these various causes. Accordingly, older people-who are at high absolute risk of coronary heart disease and ischemic stroke and at low risk for injury, cirrhosis, and other alcoholrelated diseases-are most likely to benefit from low levels of alcohol consumption. In contrast, for men and women under age 40, who have relatively low absolute risk of dying from strokes, heart disease, and alcoholrelated diseases but a high ab solute risk of dying from injury, all cause mortality will increase even at relatively low alcoholconsumption levels. For example, in a 15year fol lowup of 18 to 19yearold Swedish male military conscripts, alcohol con sumption lowered the risk of cardio vascular disease, but this disease only accounted for 4 percent of all deaths. Conversely, injury deaths, which ac counted for 75 percent of all deaths, increased among drinkers, even among those drinking seven or fewer drinks 1 In their study, Jackson and Beaglehole (1995) defined "heavier" drinking as four or more drinks per day. Accordingly, "lightto moderate" drink ing was defined as up to three drinks per day. 2 An ischemic stroke is caused by a blocked blood vessel in the brain. A hemorrhagic stroke is caused by bleeding from a blood vessel in the brain.

Number of Drinks per Day
Cirrhosis Suicide All cancers All causes Coronary heart disease Relative risk of dying from various causes for middle-aged men consuming different alcohol amounts. More than 270,000 Caucasian men ages 40 to 59 were followed for 12 years; their death rates and causes of death were analyzed according to their alcohol-consumption levels. The relative risk is the ratio of the death rate from a specific cause among a certain group of drinkers to the death rate from the same cause among abstainers. A relative risk of less than 1.0 indicates a protective effect of alcohol consumption; a relative risk of greater than 1.0 indicates a detrimental alcohol effect.
SOURCE: Bofetta and Garfinkel 1990. per week (Andreasson et al. 1988). Fi nally, the absolute risk of death from injury or coronary heart disease is low er in young women than in young men, leading to an increase in allcause mortality even in young women who are light drinkers (less than two drinks every 3 days) compared with abstainers (Fuchs et al. 1995). When interpreting these findings, however, one also must keep in mind that when researchers ex press alcohol consumption in terms of average drinks per day or per week, they often do not ascertain people's actual drinking patterns. Thus, both a person having one drink each evening and a person having seven drinks on a Saturday night (i.e., a binge drinker) average seven drinks per week. Yet their risks of alcoholrelated injuries will differ significantly, with a much higher risk for the binge drinker. These observations allow the follow ing conclusions: First, for men in their forties and postmenopausal women, the mortalityrelated benefits of light tomoderate drinking begin to outweigh the risks. Among women ages 50 to 70, however, allcause mortality appears to be reduced only among those with at least one major risk factor for coro nary heart disease (Fuchs et al. 1995). Second, the mortalityrelated benefits of lowlevel alcohol consumption

ASSESSING ALCOHOLASSOCIATED RISKS BASED ON ALCOHOL CONSUMPTION
One indirect measure of alcohol associated risks is per capita alco hol consumption. This approach is based on the observation that a per son's likelihood of experiencing negative consequences of drinking increases with the amount of alcohol consumed. Researchers are there fore closely monitoring trends in alcohol consumption.

Recent Trends in Alcohol Consumption
Following Prohibition, per capita alcohol consumption in the United States generally increased, reaching its peak in 1980 and 1981. Since then, alcohol consumption primarily has been declining. In 1993, the latest year for which complete data are available, per capita consump tion of all alcoholic beverages com bined reached its lowest level since 1964 (Williams et al. 1995). For the consumption of any kind of bever age, beer ranked fourth (behind soft drinks, coffee, and milk) in per capita consumption, a position it has held for many years. Beer also accounted for 57 percent of the absolute alcohol each person con sumed; wine represented 13 percent; and spirits made up the remaining 30 percent, the lowest level for the consumption of spirits in 50 years (Williams et al. 1995).
To estimate total and per capita alcohol consumption, researchers rely on data such as alcoholic bev erage sales, production, and tax revenues. Based on these data, the total apparent alcohol consumption for the United States in 1993 in cluded approximately 5.8 billion gallons of beer, 454 million gallons of wine, and 341 million gallons of spirits (Williams et al. 1995). These amounts translate into 303 12ounce cans of beer, 58 5ounce glasses of wine, and 142 mixed drinks contain ing 1.5 ounces of distilled spirits for every man and woman age 14 and older in the country (Williams et al. 1995).
Although per capita alcohol con sumption is a robust and useful meas ure of alcoholconsumption trends, it is only a relatively crude indicator of alcoholrelated risk, because it assumes that every person in the population of interest drinks and that all people consume equal amounts of alcohol. In general, however, drinking patterns vary significantly among the members of a population.

Drinking Patterns and Associated Outcomes
Slightly more than onehalf of American men and onethird of American women age 18 and older were current drinkers in 1992 (Dawson et al. 1995). Moreover, despite the fact that the legal drink ing age is 21, alcohol use is common among young people. Approximately 56 percent of 8th graders, 71 percent of 10th graders, and 80 percent of 12th graders report having used al cohol at some time in their lives (Johnston et al. 1995). (For more in formation on the drinking patterns of adolescents and young adults, see the articles by Chassin and DeLucia,and Quigley and Mar latt, When evaluating individual risk based on these data, one must re member that actual alcohol con sumption is unevenly distributed (see table) and that the 10 percent continue to outweigh the risks for peo ple in their sixties, seventies, and eight ies (Jackson and Beaglehole 1995).

Limitations to Risk and Benefit Assessment
Although it is clear that increasing levels of alcohol consumption are as sociated with greater physical and psy chosocial hazards, the level at which the risks outweigh the benefits cannot be determined precisely. In assessing benefits and risks, the level of precision primarily depends on the supporting evidence that is available. To determine a specific risk or benefit associated with a given level of alcohol consumption, one must be able to measure accurately both the drinking level and the condi tion in question. Thus, significant un derreporting of drinking levels could lead to an apparent increase in risk at low consumption levels.
Likewise, it may be difficult to as certain the prevalence of particular alcoholrelated conditions (e.g., cir rhosis). For example, autopsy studies suggest that as many as onehalf of all cirrhosis patients remain asymptomatic throughout their lives. At present, a needle biopsy 3 is the only definitive way to diagnose cirrhosis in a person without symptoms of liver disease.
Thus, to ascertain the true incidence and prevalence of cirrhosis among drinkers with different consumption levels, one would need to perform liver biopsies on a large sample of "healthy" subjects. For ethical and technical reasons, such a study is not feasible. Accordingly, although it is clear that a correlation exists between alcohol consumption and cirrhosis, the exact amounts of alcohol-especially at lower 3 A needle biopsy is a procedure in which a hollow needle is inserted through the patient's skin into the organ under investigation (e.g., the liver) to retrieve a small tissue sample for fur ther examination. of drinkers who drink most heavily account for 50 percent of all alco hol consumed (Malin et al. 1982). The chances of experiencing nega tive consequences of drinking (e.g., accidents or medical problems) grow with increasing alcohol consump tion. Accordingly, the remaining 90 percent of drinkers who drink only lightly or moderately should be at a small risk for a negative outcome (assuming, that is, that they do not consume their entire weekly alcohol allowance within a couple of hours on a Saturday night just before driving).
The assessment of individual risk is further complicated by the significant variability that exists in individual vulnerability to alcohol's negative consequences. For exam ple, not every heavy drinker will develop alcoholic cirrhosis. In fact, only 15 to 30 percent of the heaviest drinkers (i.e., alcoholics in treatment) are ever diagnosed with cirrhosis (Dufour et al. 1993). (For more information on potential problems associated with ascertaining the actual prevalence of cirrhosis, see the main article.) At the same time, a nonalcoholic woman consuming two drinks per day may develop cirrhosis (Dufour et al. 1993). These observations indicate that in addition to alcohol consumption,  Dawson et al. 1995. consumption levels-that lead to cir rhosis cannot be determined accurately.
Other variables influencing the assessment of net outcome include the following: • Time: What may be a health bene fit at one point in time may be a health risk at another.
• Subjective values: What one per son may perceive as a benefit, another person may perceive as neutral or harmful.
• Social components: The benefit to one person may be a risk to an other person or to society as a whole.   Per Capita Alcohol Consumption: National, State, and Regional Trends, 1977-1993. Bethesda, MD: National Institute on Alcohol Abuse and Alcoholism, 1995 tion may confer longterm cardiopro tection; however, the boy's chances of dying of a heart attack as a teenager are exceptionally small. On the other hand, alcoholrelated traffic accidents are among the leading causes of death for teenagers (Dufour 1994). Drink ing therefore produces a net risk for this boy.

Risk Now Versus Benefit and Risk
Later. One of the hallmarks of alco hol dependence is loss of control over drinking; recovering alcoholics often cannot maintain moderate drinking patterns. Consequently, moderate drink ing likely will escalate in this highrisk group to heavier drinking, with all its attendant risks for injury and chronic disease. Therefore, moderate alcohol consumption poses a net health risk for recovering alcoholics, even though it also may have cardioprotective effects.
Benefit Now and Later. A 55yearold postmenopausal woman who has risk factors for heart disease may benefit from alcohol's cardioprotective effects. If she takes no contraindicated medi cations, lowlevel alcohol consump tion may confer a net benefit to her.

Benefit Now Versus Risk Now.
For a 55yearold postmenopausal women with risk factors for heart disease and a strong family history of breast cancer, assessment is more difficult. Heart disease is the leading cause of death for American women in that age group, and breast cancer is the second most common cause of cancer deaths among women (National Center for Health Statistics 1993). Currently, it is un known whether moderate drinking would confer a net risk or a net bene fit for the woman in question, because the same low consumption levels have been associated with both alcohol's cardioprotective effects and increased risk of breast cancer. Once researchers have elucidated the exact mechanisms by which alcohol contributes to cardio protection and breast cancer, a more accurate assessment of this woman's net outcome will be possible.

Benefit to One Person Versus Harm to Another.
For a woman early in the first trimester of pregnancy, a few drinks most likely will have no net harmful effects for the woman herself. This level of alcohol consumption, how ever, may have serious negative con sequences for the developing fetus. Thus, maternal drinking during preg nancy constitutes a net risk for the fetus. Currently, one cannot predict whether a given fetus will be injured by a specific alcohol amount or whether a safe threshold of alcohol consumption during pregnancy exists below which no fetal damage occurs.
Until researchers can answer these two questions, the safest course is for women to avoid all alcohol consump tion during pregnancy.

CONCLUSIONS
The ultimate goal of assessing the risks and benefits associated with alcohol consumption is to provide recommen dations that promote a healthy lifestyle and thus extend people's lives. Yet despite all the advances in medical and genetic research, the effects of these recommendations on the indi vidual cannot be determined. Another medical example illustrates this point. Tsevat and colleagues (1991) have calculated that if people changed their behavior to eliminate all heart disease, the average life expectancy would in crease by 3.1 years for a 35yearold man and by 3.3 years for a 35year old woman. However, these 3 added years of life are just a statistical aver age. The actual benefits of a healthy lifestyle to a given person may be far greater or far less and cannot be pre dicted in advance. With these qualifications in mind, assessment of alcoholassociated health risks and benefits leads to the following alcoholconsumption recommendations: • For certain groups of people, alco hol consumption is associated with a net health risk, and thus abstinence is the safest course. These groups include women who are pregnant or trying to conceive, recovering alco holics, people about to operate a motor vehicle or other dangerous machinery, and people having medi cal contraindications or taking med ications that interact with alcohol.
• Middleaged and older adults who do not fall into any of the above mentioned exclusionary categories and who enjoy consuming alcohol in moderation are likely to experi ence net health benefits.
• Heavier drinkers likely will benefit from moderating their consumption.
The Dietary Guidelines for Ameri cans (U.S. Department of Agriculture and Department of Health and Human Services 1995) recommends drinking levels of no more than one drink 4 per day for women and two drinks per day for men. Because each person's cir cumstances vary, however, people should discuss these recommendations with their physicians or other health care providers.
Finally, although the prospect of net health benefits from moderate drink ing may appeal to people, it generally is not the only or primary reason for drinking. Instead, most people drink because they like alcohol's taste, ef fects, or both. The remaining articles in this journal issue discuss in more detail the reasons for and consequences of drinking across the life span. ■